In the latest round of a wave of cyberattacks on Russian targets, the official websites of the Russian Federation’s president and central bank were taken offline this morning in what the Kremlin’s press office called a “serious DDoS attack.” The attack also targeted “a number of other Web portals,” according to the Kremlin statement. The sites are back online for most users, but the attack is still ongoing.

Anonymous Caucasus, the “Electronic Army of the Caucasus Emirate,” has claimed responsibility for the attack on its Facebook page with a statement saying, “This is just warming up, Russian pig!”

According to a report from the state-sponsored RT.com, the Russian Foreign Ministry’s site was also disrupted today, following a number of attacks on the websites of Russian media outlets on Thursday. Anonymous Caucasus also claimed responsibility for attacks on a site operated by the largely state-owned national television network Russian Channel One and the Russian DDoS attack protection firm Esteq, stating through Twitter that it had “nothing to do with Ukraine, or all current events in this country.”

GigaOM speculated that the attacks are connected with the Kremlin’s recent move to block three independent Russian news sites with “an anti-Putin bent.” On Thursday, Roskomnadzor (Russia’s Federal Service for Supervision in the Sphere of Telecom, Information Technologies and Mass Communications, an authority established by a Putin decree in 2008) ordered ISPs to block a number of sites the government claimed were inciting violence—including ej.ru, which has covered protests in Russia over the sending of troops to Ukraine, and the activist news site Kasparov.ru.